Ultrasonic cleaning apparatus basket assembly



Nov. 1, 1960 ER 2,958,332

ULTRASONIC CLEANING APPARATUS BASKET ASSEMBLY Filed Sept. 19, 1958 A TTOKPNE V United t tes Hassan E. Schueler, St. Albans, N.Y. (110Gristmill Lane, Saddle Rock, Great Neck, N .Y.)

Filed Sept. 19, 1958, Ser. No. 762,040

'4 Claims. (Cl. 134-469) The instant invention relates to ultrasoniccleaning devices for particularly surgical instruments, hypodermicneedles, syringes, cannulae, glassware and generally all types ofarticles having an internal bore of relatively small diameter.

Ultrasonic cleaning is commercially feasible at frequencies of from 15kilocycles to about 1,000 kilocycles per second of such amplitude thatcavitation is produced in a cleaning liquid. Cavitation is generallyaccepted as the rapid generation and violent collapse of very minutebubbles in the cleaning liquid which results in numerous though smalland intense impacts on solid surfaces within the liquid. The intensehigh-frequency vibrations required in the cleaning liquid aretransferred from an electrical oscillation generator to the liquid by atransducer converting the electrical power into mechanical motion. Thetransducers may be of the piezoelectric, for example, barrium titanate,or the magnetostrictive, for example nickel, types and requirerelatively large radiating surfaces. The transducers most frequently arecoupled to the bottom of the cleaning tank, but may be, and sometimesare, mounted on the sides of the tank to permit greater depths ofcleaning fluid so that the material to be cleaned is as close aspossible to the radiating surface of the transducer. The cleaning liquidmay be water or an aqueous or solvent solution from which excessive airor vapor has been removed, and at a temperature which is generally lowerthan the temperature of the cleaning fluid of other cleaning methods.

One of the difliculties which has slowed up general adoption ofultrasonic cleaning apparatus in hospitals is that it has been notedthat the small bore instruments were not readily cleanable in theirinteriors. More often than not, the cores were still dirty and cloggedwith foreign matter, such as dried blood, solution stains, etc., evenafter long periods in the ultrasonic cleaning apparatus. It would appearthat the air entrapped in the narrow bores of the needles, syringes,etc., when placed in the cleaning tank did not permit the cleaning fluidto enter the bore and that cavitation therewithin thus could not takeplace, or that the metal of the instrument cut off the cavitation withinthe bores. Whether thi is the correct explanation or not I am uncertain,but the observed fact of dirty and clogged bores even after lengthyperiods in the liquid in ultrasonic cleaning tank cannot be disputed.

An object of this invention is to provide an accessory device forultrasonic cleaning apparatus by which cleaning of the bores of smallarticles, such as surgical needles, cannulae, syringes and the likewhere antiseptic cleanliness is a must, is accomplished by cavitation inthe liquid within the bore.

I accomplish the foregoing object, and others, by providing an insertinto the cleaning tank which has a plurality of spaced upwardlyprojecting wires of preferably spring metal which fit into the bores ofthe instruments to be 2,958,332 Patented Nov. 1, 1 960 cleaned with someclearance radially. that the projecting wires may vibrate within thebores and produce cavitation of'the cleaning liquid within the bores.The wire projections may be of various diameters and various lengths tofit difierent size bores and different lengths thereof, with theprojecting wire lengths such that the preferable extend somewhat throughthe open upper end of the bores. The base of the insert of my inventionis positioned close to the transducer radiating surface to permit thefull effect of cavitation to occur. To have the upwardly projectingwires vibrate mechanical as much as possible, the lower end regionsthereof may be in the form of an open helix, and the lower ends ofsuccessive pairs of the projection wires may be integral with eachother.

My invention will more readily be understood from the followingdescription of an illustrative embodiment thereof when read inconjunction with the appended drawing of which the sole figure shows, inelevational section, a batch-type ultrasonic cleaning apparatus equippedwith the tank basket of my invention.

The ultrasonic cleaning apparatus comprises a cleaning liquid containingtank 1 supported on the housing 2 of the transducers 3, actuated byoscillation generator 4-, the latter being shown as external to thehousing 2 but which may well be incorporated therewith. The transducers3, of which there are a plurality, for example twenty-eight arranged infour rows of seven each, are mechanically coupled directly to the bottom5 of the tank in which cleaning fluid 6 is filled to a predeterminedlevel. For ease of illustration, the tank has been taken as rectangularin shape but it may be of any desired shape.

The basket 7 of my invention is provided with a plurality of spacedwires projecting upwardly substantially vertically which may be ofidentical shape, and length, altho I have shown several different formson a single basket. Thus projecting wires 8 through 15 have a helicallower end region which is coaxial with the upper straight wire portionthereof, and wires 16 through 18 are straight their whole length. Whilewires 10, 15 and 16 are attached to the bottom of the basket 7, wires 8and 9, 11 and 12, 13 and 14, and 17 and 18, are continuous in pairshaving their individual lower ends pass through the bottom of the basketso that the interconnecting portion of each pair rests on tank bottom 5with the basket in place. It will be noted that the bore of each needle,for example 19, to be cleaned, is threaded on the straight portion ofthe upright projection, the helical lower end, if any, of the uprightprojecting wire being of such diameter and length that the larger boreend of the needle, or other article, rests on the basket bottom. Theopen basket 7 has a plurality of perforations 20 in each of its sidewalls, as also its bottom, to permit free flow of the cleaning liquidtherethrough, and a pair of finger apertures 21 at the top region of atleast a pair of opposite side walls to permit ready placing thereofinto, and removal from, the tank. A plurality of feet 22, of relativelysmall height, may be integral with the basket bottom exterior to providespacing between the basket and the tank bottom.

What I claim is:

1. A basket for supporting small bore articles in ultrasonic cleaningtanks having a bottom and side walls defining a plurality of aperturesfor flow of liquid into the basket on insertion into a tank, a pluralityof spaced supporting wires extending upwardly from the basket bottomhave at least their upper portion straight, and at least some Wires ofthe plurality having their lower end region wound in an open helixcoaxial with a straight upper portion of the wire.

2. The tank basket according to claim 1 in which at least some of twoadjacent supporting wires having the helical regions are interconnectedat their lower ends, the interconnecting portion thereof passing throughand along the bottom of the basket.

3. The tank basket according to claim 1 in which the diameters of thestraight portion of the supporting wires 6 References Cited in the fileof this patent UNITED STATES PATENTS Van Horn Nov. 12, 1895 Nesbitt Dec.31, 1912 Abbott Mar. 1, 1938 Murdoch Sept. 30, 1958 FOREIGN PATENTSSwitzerland July 14, 1956 Germany Jan. 30, 1937 Great Britain Feb. 5,1958

